Clutch control device



y 19, 1942- H. E. CLARKE 2,283,423

CLUTCH CONTROL DEVICE Filed Aug. 25, 1940 2 Sheets-Sheet 1 hats 1.5.

May 19, 1942. H. E. CLARKE CLUTCH CONTROL DEVICE 2 Sheets-Sheet 2 FiledAug. 23, 1940 v ,Eaj 270 07" fqrozcz (ff 6264x7736, f A? ibis is.

u lfl lulllllllllllll Iv a ll I Ill Ir 17 fI/l/f/I'l/ V Patented May 19,1942 UNETED STATES?ATENT OFFICE clutch control device, and moreparticularly to means for automatically controlling the engagement ofthe motor vehicle clutch thus eliminating the necessity for manualcontrol forclutch 7 engagement by foot pressure applied to the clutchpedal as it is allowed to return.

The present application discloses improvements over the clutch controldevices disclosed in my earlier applications Serial No. 202,256, filedApril 15, 1938, Patent No. 2,230,132, issued January 28, 19 11, andSerial No. 230,047, filed September 15, 1938, Patent No. 2,215,496,issued Sept. 24, 1940. :In each of the above applications I havedisclosed a liquid dash pot device T clutch and the movement of theaccelerator;

which has a compensating action.

It is an object of the present invention to provide an automatic clutchcontrol device including a dash pot having valve means controlling theescape of fluid from the dash pot chamber in which the valve, as theclutch approaches engagement, is movable between spaced ports whichallow escape of fluid and a more rapid movement of the clutch as thevalve is moved in either direction from its retarding positionintermediate the ports, and to control the movement of the valve by thecombined action of the relative movement of the plunger with respect tothe cylinder responsive to clutch movement, and the compensatingmovement of the accelerator pedal.

More specifically, it is an'object of the present invention to provide aliquid dash pot device for automatically controlling the engagement of aclutch comprising a plungermovable with ment thereof as disclosed in theattached drawings in which:

Fig. 1 is a diagrammatical broken elevation showing the installation ofmy clutch control device;

Fig. 2 is a vertical section taken through the dash pot unit of theclutch'control device;

Fig. 3 is a plan view of the upper end ofthe dash pot showing themounting and controls therefor;

Fig. 4 is an enlarged View, partially shown in vertical, section, of thelower end of the valve rod;

Fig. 5 is an enlargedelevation of the lower end of the dash pot plunger;H Fig. 6 is a horizontal section taken onthe plane indicated 6-6 of Fig.2 and showing the at rest position of the parts;

Fig. 7 is a View similar to Fig. 6 but showing the parts in positioncorresponding to full disengagement of the clutch;

Fig. 8 is a viewv similar to Figs..6 and 7 showing the parts inretarding position for slow movement of the clutch as it approachesengagement; and V Fig. 9 is a diagrammatic view showing a modificationof the accelerator control of the flexible cable.

The operating parts may be installed generally similar to thedisclosure'in my priorapplication Serial No. 230,047, filed September15, 1938,-

usual accelerator pedal l4 pivoted at It. Movement of the acceleratorpedal will engage a lever 18 which is pivotally mounted on a bracket 20mounted in some suitable fixed position beneath the dash of the vehicle.The lever l8 has an arm 22 which engages the ball member 24 secured toone end of a flexible cable 26. The cable 26 runs through a flexibleconduit 28, one end of which has a screw threaded membertil threadedinto an extension 32 from the fixed bracket. 20. This connection permitsshortening or lengthening of the flexible conduit 28 between thetwosupported ends thereof, A dash pot cylinder 3611s fixed in somesuitable manner, such as by the bracket 36, to the clutch pedal orothenmovable part of the clutch. An L-shaped bracket 38 is fixed to adash pot plunger 40 slidably associated with the dash pot cylinder 34.The bracket 33 is. pivotally connected to a clamp bracket 42 by means ofthe pivot bolt 44 secured by the nuts 45 and 45. An arm 4'! is fixed tothe outer end of the bolt 44 by a clamp bolt 48. The bracket 42 is fixedto the steering post 49 by means of a clamp bolt 56.

The flexible conduit 28 is clamped to the fixed arm 41 by a screw 52.The flexible cable 26 is connected to a ball 54 received in an openingat one end of a lever arm 56. The arm 56 is fixed by a set screw 58 to areduced extension 69 from the valve rod 62. The arms 56, when at rest,may engage a stop 6| under the force of a tension spring 63 connected toa screw 64 at one end of the arm 56 and to a pin 66 fixed to the bracket38. The movement of the arm 56 in a clockwise direction from theposition shown in Fig. 3 is limited by an adjustable screw threadedvalve ports with the accelerator closed will be in the relativepositions shown in Fig. 6. Depression of the clutch pedal I6, therebydisengaging the clutch, will tend to pull the dash pot cylinder downwith respect to the piston rod. At the same time, due to the mounting ofthe parts, the dash pot cylinder 34, as shown in Fig. 1, will tend toswing about the pivot bolt 44, and in Fig. 1 this movement would be in aclock-wise direction. This swinging movement of the cylinder stop member68 which is mounted in the fixed arm 41.

The dash pot cylinder, which has been generally indicated 34, includesan outer cylinder I6 and an inner cylinder I2, concentrically mounted toprovide a chamber I4 between the cylinders which constitutes an oilreservoir. The cylinders I6 and I2 are secured at their lower ends to abase plate I6 by which the dash pot cylinder is pivotally mounted on theclutch pedal. The upperends of the cylinders I6: and 12 are secured by aclosure I8, which is provided with vents 86 to lead any oil reaching thetop of the inner cylinder I2 back into the reservoir I4. The dash potchamber 82, at the bottom of the inner 'cylinder I2, is placed undercompression by an enlarged piston head 84 of the piston rod or plungerThe head 84 closely fits the inner wall of the cylinder I2. Therotatable valve rod 62 is mounted in the hollow piston rod 46 and heldagainst vertical displacement by the bushing 86 which is pressed intothe upper end of the plunger 46. The valve rod is of somewhat smallerdiameter than the interior of the plunger, but a bushing 88 is providedat the lower end of the piston rod to make a close fit between the valverod and the plunger. A relief opening 89 may be provided in the plunger46 at the upper end to allow the escape of oil which may leak past thebushing 88.

As shown in Fig. 4, the valve rod 62 has an opening 96 drilled into thelower end thereof. A

slot 92 is cut into the side of the rod 62 into communication with thevertical opening 96.

The slot 92 forms a valve port which cooperates as the valve rod isturned, with a first port 94 and a second port 96 drilled radiallythrough the piston rod 46 and bushing 88. The ports 94 and 96 may besomewhat enlarged at their outer ends to receive balls 98 and I66 which,as will be explained hereafter, are used to prevent noise.

The cylinder I2 has relatively small by-pass ports I62 which function toallow fairly rapid movement of the piston rod, with respect to the dashpot cylinder until the ports I62 are closed by the head 84 of thepiston. Openings I64 may also be provided at the upper end of thecylinder to allow the oil above the piston head to return to thereservoir. A removable plug I66 is shown on the side of the outercylinder I6 which, upon removal, permits filling of the oil reservoir.The plunger head 84 may have a rawhide sealing washer I68 to preventleakage of oil past the plunger head.

It will be understood that in normal, at rest, position, that is, withthe clutch fully engaged, the piston head will be near the bottom'of thedash pot chamber as shown in Fig. 2, and the and piston rod tends totension the cable 26. Initially, as the cable is moved the lever I8 willbe moved in a counter clock-wise direction until it contacts theaccelerator pedal I4. Further movement of the cable will tend to swingthe valve arm 56, as shown in Fig. 3, in a clock-wise direction awayfrom the stop 6| and towards the adjustable stop 68. The movement of thearm 56 will thereby rotate the valve rod 52 from the position shown inFig. 6, past the position shown in Fig. 7 and to a position such asshown in Fig. 8. If the gear shift lever is then placed in position forlow speed and the operator drops his foot from the clutch pedal, thepedal I6 will quickly return while the piston head 84 is travelingtowards the by-pass ports I62. After the ports I62 have been closed,however, by the piston head, the oil will tend to become compressed inthe dash pot cylinder and will be forced to escape-through the verticalpassage 96 in the valve rod 62. This escape, however, is temporarilyprevented as during the first portion of the return movement of theclutch pedal the valve rod 62 has been rotated counter clock-wise fromthe position shown in Fig. 8 to a position such as shown in Fig. I.There will be a very slight leakage of oil sincethe parts are closely,but not tightly, fitted, and this slow leakage and movement of the partswill occur as the clutch is about to engage. The parts are so adjustedthat the clutch will not-come in so rapidly as to cause stalling of theengine, and also so that the clutch will not come in so slowly thatunnecessary wear, due to slipping of the clutch occurs.

The space between the relatively small ports 94 and 96 is only slightlylarger than the slot or port 92 whichis cut into the valve rod 62. Whenthe port 92 is in the retarding position shown in Fig. '7 intermediatethe ports 94 and 96, the movement of the clutch is so slow that it isalmost stopped. The retarding of the clutch to bring it almost to a stopmay be very accurately adjusted with respect to the engagement of theclutch by turning the screw threaded member 36 to lengthen or shortenthe flexible conduit 28 between the supporting ends thereof. If, forexample, the member 36 is turned to move upwards with respect to itsbracket 32, the valve rod 62 would be turned a little farther as theclutch pedal is depressed to disengage the clutch which will causeretardation of the clutch a little later as the pedal returns, While ifthe member 36 is screwed downwards so as to shorten the conduit 28, theretardation will occur earlier. This adjustment may be made so that thevehicle will start in low speed without stalling of the engine eventhough the accelerator is not moved. The very slow movement of theclutch as it is about to engage will take place due to a very slightleakage of oil, but as the rod 62 comes into communication with the port94 the oil is allowed to escape more rapidly bringing about full clutchengagement and full return of the clutch pedal to its normal position. l

The action thus far has been explained without referring'to the effectproduced by movement of the accelerator pedal. Assuming again that theclutch has been disengaged by depression of the'clutch pedal, the normaloperation would be, after engaging the gears, to remove the foot fromthe clutch pedal and then to slowly depress the accelerator pedal as theclutch engages and the vehicle picks up speed. Depression of theaccelerator pedal [4 will-cause movement of the lever I8, the spacebetween'the pedal l4 and lever l8 being closedby the relative positionof the clutch pedal. The action of the accelerator movement, as thethrottle is opened, will be to pull the cable 26 through the flexibleconduit 28 and to rotate the arm 55 and valve rod 62 in a clock-wisedirection from the position shown in Fig. 3. Thus, although the clutchpedal may have returned so that-the valve rod 62 is in the retardingposition shown in Fig. 7, depression of the accelerator will tend torotate thevalve stem until the port 96 is opened as shown in Fig. 8.This will bring about a more rapid closing of the clutch which isdesirable-as the gear is shifted into higher speeds. If the acceleratoris allowed to return to close the throttle before 'full engagement ofthe clutch has occurred, the valve rod 62 will be rotated counterclockwise tending to bring the valve port 92 into communication with theport 9d, thus bringing about full engagement of the clutch and fullreturn of the clutch pedal to its normal position.

In the installation of my clutch control mecha nism, the relativelymovable dash pot cylinder and plunger are mounted, respectively, on theclutch pedal and steering post as shown in Fig. 1, it beingunderstood'that other forms'of mounting may be resorted to in whichrelative movement of the cylinder and plunger occurs responsive tomovement of the clutch. "The brack-' I ets 36 on the clutch pedal and 42on the steering post are so positioned that'the ports I02 will be closedby the plunger head 84 just prior to initial engagement of the clutchplates. The screw threaded member 30 is adjusted as previously describedso that the full retarding effect of the dash pot means comes intooperation just as the clutch is about to engage and provides a smoothpick-up without'stalling of the engine. The stop 68 is adjusted toprovide a limit for movement of the arm 56 responsive to depression ofthe "accelerator pedal and it'will be-understood that this stop tends toprevent opening the throttle of the engine too Wide in view of therelative position of the dash pot cylinder and piston, but that theoperator may still press the accelerator pedal down due to springing'ofthe arm I8. The stop 68 is carried by the fixed part 41 while the arm 56is movable with the plunger All as the plunger swings about the pivot44. Disengagement of the clutch, producinga swinging movement of theplunger 40 with respect to the pivot 44, results in movement of the arm56 in a clockwise directionfrom the position shown in Fig. 3 after thepedal controlled arm 18 has come into contact with the accelerator pedalI i. In this position depression of the accelerator peda1 causingopening movement of the throttle tends to further move the arm 56 in aclockwise direction. The arm 55 is free to move in this position sinceit is swung away from the stop 68. When the clutch pedal is allowed toreturn, the swinging movement of the plunger 40 will bring the arm 56into contact with the stop 68 to positively move the arm 56 towardsclosed position just-as the clutch is about to engage. Itwillbeunderstood that this action may be" controlled byadjust-ment of the stop'68. The movement of the arm 56 in counter-clockwise direction as theresult of contact with the stop 68-is a positive movement independent ofthe position of the accelerator pedal or of the engine throttle. The

effect is to substantially stop the -movement of the clutch just as itis about toengage. The

I balls 98 and I00, shown in Figs. 6, '7 and 8, are

' not intended to serve the purpose of check valves but are used toprevent noise which may otherwise occur as the clutch pedal is thrownout and the'piston 4U raised with respect to the cylinder I2. Theprovision of the balls 98 and 169 prel5 vents the entrance of the oilthrough the relatively small openings 94 and 96 whereby the oil is notsucked into the dash pot chamber 82 until the piston head 8 1 has passedthe openings I02 which allow the oil to flow from the reservoir.

" lt will be understood that as the clutch engages further movement ofthe accelerator is permitted.

In Fig. 1 the accelerator pedal is not directly connected to the cable26. A modified form of installationis shown in Fig. 9 in which theaccelerator pedal 14 is connected to the cable 26 through a stiff springI Ill. The spring serves the same purpose as the lost motion between theM pedal 14 and lever I8 in-Fig. 1. It Will be fur- 30 ther understoodthat some similar form of connection between the cable 26 and a movablepart of the throttle actuating means may be resorted to if the clutchcontrol device is installed under the hood. I

I'claim: 1. In a mechanism for automatically control- "ling theengagement ofa motor vehicle clutch, dash pot means comprising acylinder and a plunger member cooperating therewith relative- 40 1ymovable responsive to movement of the clutch 'wliereby saiddashpot-means acts to retard the engagement of the clutch, means to variablyregulate the rate of retardationbyrestricting the escape of fluid fromthe dash pot chamber comprising -a valve member associated with saidplunger memberand movable relatively 'there to, one of said membershaving a single escape passage and the other of said members having apair of escape passagesand control means'ior 'causing relative movementbetween said members to bring said single passage into communicationwith one of said pair of passages or to close said single passage whenintermediate "said pair of passages. f

2. In a mechanism for controlling the engageits ment of a motor vehicleclutch, dash pot means including a cylinder and a plunger cooperatingtherewith, means for producing relative move- 'ment between saidcylinder and plunger rep sponsive to the movement of the clutch wherebysaid dash pot means acts to retard the engagement of the clutch, valvemeans variably con- "trolling the retarding effect of the dash pot meanscomprising relatively movable valve members, one of which is providedwith a pair of spaced valve ports and the other of which is providedwith a single valve port, means for limiting' the relative movement ofsaid valve members whereby said singleport at any time is incommunication with one of said pair of ports or is in a closed positionintermediate said pair of ports and means for controlling the relative IV movement between said valve members.

"3. 'In a mechanism for controllingthe engage ment of a motorvehicleeliit'ch' a daislrpot cylinling the engagement of a motor vehicleclutch,

der having a compression chamber and a reservoir, a dash pot plungerrelatively movable with respect to said cylinder, valve meansrestricting the escape of fiuid from said compression chamber towardssaid reservoir, comprising a rotatable valve rod fitting within saidplunger having a single valve port in the side wall thereof and apassage leading to said valve port from the compression chamber, saidplunger having a pair of; circumferentially spaced valve ports throughwhich the fluid may escape towards the reservoir, means responsive tomovement of the clutch for producing relative movement between saidcylinder and plunger and simultaneously causing relative movementbetween said valve rod and said plunger whereby the valve port in saidvalve rod is moved in one direction into communication with one of saidpair of ports in said plunger to permit rapid movement of the clutchjust prior. to engagement, and whereby said valve port in said valve rodis brought into communication with the other of said ports in saidplunger to permit rapid movement of the clutch to complete' theengagement, and whereby the movement of the clutch while it is engagingis retarded as said 5 single valve port moves between said pair ofports.

4. In a mechanism for automatically control.

dash pot means including a liquid filled compression chamber and areservoir, and a relatively movable cylinder and plunger movableresponsive to movement of the clutch to retard the engagement of theclutch, a relatively rotatable valve rod received within said plungerand having a liquid escape passage leading from the compression chamberto a single valve port in the side wall of said valve rod, said plungerhaving a pair of escape ports through which the liquid may flow towardsthe reservoir, said single valve port; being normally in communicationwith one of said pair of ports and means for moving said .valve rod tobring said single valve port into communication with the other of saidpair of ports responsive to disengagement of the clutch said valve rodmoving back past a retarding posi-'- tion as the single valve portpasses between the pair of ports whereby clutch movement is retarded asit is about to engage.

5 In a mechanism for automatically coni,50; trolling the engagement of amotor vehicle clutch, dash pot means including a liquid filledcompression chamber and a reservoir, and a relatively movable cylinderand plunger movable responsive to movement of the clutch to retard theengagement of the clutch, a relatively rotatable valve rod receivedwithin said plunger and having a liquid escape passage leading from thecompression chamber to a single valve port in the side wall of saidvalve rod, said plunger having a pair of escape ports through which theliquid' may flow towards the reservoir, said single valve port beingnormally in communication with one of said pair of ports and means formoving said valve rod to bring said single valve port into communicationwith the other of said pair of ports responsive to disengagement of theclutch, said valve rod moving back past a retarding position as thesingle valve port passes between the pair of ports wherebyclutchmovement is re tarded as it is about to engage and means responsive tomovement of the throttle control of the vehicle tending to cause furthermovement of the valve rod in order to obtain a faster engagement of theclutch.

6. In a mechanism for automatically controlling the engagement of V amotor vehicle clutch, dash pot means including a cylinder and a plungermember cooperating therewith relatively movable responsive to movementof the clutch, said cylinder and plunger enclosing a compression chambereffective to retard the engagement of the clutch, a relief passageleading from the compression chamber, valve means variably controllingsaid relief passage and the rate of retardation of the engagement of theclutch, means operatively connected to said valve means tending to opensaid relief passage and decrease the retarding action responsive toopening movement of the throttle and positively acting means effectiveto substantially close the passage and prevent escape of fluid from thecompression chamber independent of the position of the throttle as theclutch approaches engagement to substantially stop the movement of theclutch before it is fully engaged.

7. In a mechanism for automatically controlling the engagement of amotor vehicle clutch, dash pot means including a cylinder and a plungermember cooperating therewith relatively movable responsive to movementof the clutch, said cylinder andv plunger enclosing a compressionchamber efiective to retard the engagement of the clutch, a reliefpassage leading fromthe compression chamber, valve means variablycontrolling said relief passage and the rate of retardation of theengagement of the clutch, means operatively connected to said valvemeans tending to open said relief passage and decrease the retardingaction responsive to opening movement of the throttle and positivelyacting means effective to move said valve means towards substantiallyclosed position independent of the position of the throttle as theclutch approaches engagement.

8. In a mechanism for automatically con- Y ment of the clutch, a reliefpassage leading from the compression chamber, valve means variablycontrolling said relief passage and the rate of retardation of theengagement of the clutch, means operatively connected to said valvemeans tending to open said relief passage and decrease the retardingaction responsive to opening movement of the throttle, positively actingmeans effective to move said valve means towards substantially closedposition independent of the position of the throttle as the clutchapproaches engagement, said valve means including a valve rod extendingthrough said plunger and movable relatively thereto and an arm fixed tothe outer end of said valve rod and said positively acting meanscomprising a fixed stop adapted to be engaged by said arm. s

9. In a mechanism for automatically controlling the engagement of amotor vehicle clutch,

dash pot means comprising relatively movable cylinder and plungermembers enclosing a compression chamber effective to retard theengagement of the clutch, one of said members being pivotally mounted ata fixed point and the other of said members being pivotally connected toa part movable in response to movement of the clutch, a relief passageleading from the compression chamber, a valve rod extending through saidplunger and movable relatively thereto, said plunger and valve rodhaving valve ports forming a variably controlled portion of the reliefpassage, an arm fixed to the outer end of said valve rod, spring meansacting upon said arm tending to move said arm and valve rod in onedirection, throttle controlled means connected to said arm tending tomove said valve rod in the opposite direction responsive to opening ofthe throttle, and an adjustable stop member mounted in fixed positionrelative to the ivotally mounted plunger and valve rod, said arm beingbrought into engagement with said stop member to limit the movement ofthe valve rod independent of the throttle controlled means.

10. In a mechanism for automatically controlling the engagement of amotor vehicle clutch, dash pot means including a cylinder and a plungermember cooperating therewith, said cylinder and plunger being relativelymovable responsive to movement of the clutch and enclosing a compressionchamber effective to retard the engagement of the clutch, 'a singlerelief passage leading from the compression chamber, valve meansvariably controlling said relief passage, means effective to move saidvalve means to open said relief passage when the clutch is fully engagedor fully disengaged, said means be ing effective to move said valvemeans to substantially close said relief passage and prevent the escapeof fluid from the com'pressionchamher to retard the engagement of theclutch as the clutch approaches engagement.

- ROLD E. CLARKE.

